Specifications
" The traditional open construction"

The thatch should be applied on a sturdy construction of rafters and batons.

The batons are fastened on the rafters.
On top of the batons a thin layer of long clean reed is placed to get a nice look from underneath.
On top of this, first comes a layer of back fill, before the main layers of thatch are applied.

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The distances between batons:

The first baton should come 200 mm from the tilting fillet.
The second baton on 150 mm above the first, every next one comes at a distance of 280 mm.
The top baton comes as high as possible on the rafters.
The one but last 150 mm below the last.
The next one 200 mm unterneath this one.
All next ones on 280 mm.
(see diagram)

The tilting fillet:

Everywhere where the thatch is extended over the under construction a barge board has to be fitted .This should stand above the underconstruction about 50mm. The exact dimensions of this depends on the reed used. (the shorter the reed, the smaller this measurement)

The first layer:

On the baton comes a first layer of very long reed. This layer makes sure that a nice look from the inside is secured. The layer is 2 to 3 cm thick.
It is placed in such a way that no seed plumes are visible.

Thickness of the layer of thatch:

If the distance from the top of the roof to the eaves does not exceed 7 meters the sloop of the roof exceeds an angle of 45 degrees, and reed is used which is shorter than 1.5 meters than the thickness of the thatch layer should be at least 25 cm on the eaves and 22 cm on the top of the roof. The wear out part of the thatch should be at least 10 cm (the part of the thatch on top of the fastening rods)
All measurement taken through the layers of thatch at a right angle on the roof construction

If the distance is more than 7 meters, or the slope is less than 45 degrees, or reed is used longer than 1.5 meter, the measurements should be at least 28 and 25 cm. (the minimal layer of wear out should in this case be at least 12 cm.
Lately there is a tendency to make thicker thatched roofs (upto 35 cm)

 

surface:

To determine the price of a thatched roof in Holland the measurement of the total outside surface is measured.

Quality of reed:

Determination of the quality of reed is very difficult. The customer should rely on the professional skills of his thatcher for this.
In the specifications of the roof the origin of the reed should always be mentioned.

Fastening the thatch:

The reed must be fastened very firmly to the construction at intervals as shown above.
The fastening rod must be of galvanized mild steel of a thickness of 5 mm
The thin binding wire is made of stainless steel

The reed is fastened somewhere between 40 and 55 cm from the end.

The thatch should not extend the construction by more than 15 cm.

Under the top tiles very often a small band of wire netting is attached to strenghten the cement and to prevent damage of the thatch by birds.

lifespan:

The lifespan of a thatched roof should be at least 25 years.
This lifespan is depending on many things such as: the slope of the roof, the reed used, the skills of the thatcher who made the roof, and the care and maintenance which it is given.
The minimal slope on which thatch can be applied is 30 degrees above a small dormer window (absolute minimum) and 45 degrees for the main roof.
If the thatch is applied to a roof with a slope less than 45 degrees, one has to be prepared to accept an even shorter lifespan.